Place the potatoes a large casserole with enough salted water to cover, and bring to the boil. Cook the potatoes until tender, 15 to 20 minutes. Drain and mash with the butter until fairly smooth.
Beat the milk in with a wooden spoon, and stir in the parsley, chives, lovage and nutmeg. Season to taste with salt and pepper.
Lovage
Lovage is an herb that has a spicy, almost celery-like flavour. If you can't find lovage, try using chervil, lemon balm, marjoram or even basil.